title: On the near-wall accumulation of injectable particles in the microcirculation: smaller is not better.
abstract: Although most nanofabrication techniques can control nano/micro particle (NMP) size over a wide range, the majority of NMPs for biomedical applications exhibits a diameter of ~100 nm. Here, the vascular distribution of spherical particles, from 10 to 1,000 nm in diameter, is studied using intravital microscopy and computational modeling. Small NMPs (≤100 nm) are observed to move with Red Blood Cells (RBCs), presenting an uniform radial distribution and limited near-wall accumulation. Larger NMPs tend to preferentially accumulate next to the vessel walls, in a size-dependent manner (~70% for 1,000 nm NMPs). RBC-NMP geometrical interference only is responsible for this behavior. In a capillary flow, the effective radial dispersion coefficient of 1,000 nm particles is ~3-fold larger than Brownian diffusion. This suggests that sub-micron particles could deposit within diseased vascular districts more efficiently than conventional nanoparticles.
authors.affiliation: Department of Translational Imaging and Department of Nanomedicine, The Methodist Hospital Research Institute, 6670 Bertner Ave, Houston, TX 77030, USA.
authors.forename: Tae-Rin
authors.initials: TR
authors.lastname: Lee
authors.forename: Myunghwan
authors.initials: M
authors.lastname: Choi
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Kopacz
authors.forename: Seok-Hyun
authors.initials: SH
authors.lastname: Yun
authors.forename: Wing Kam
authors.initials: WK
authors.lastname: Liu
authors.forename: Paolo
authors.initials: P
authors.lastname: Decuzzi
mesh_terms: D008833:Microcirculation; D008853:Microscopy / Q000379:methods; D010316:Particle Size